As a rewritable non-volatile memory, a semiconductor memory device of the stacked gate structure, which is represented by the flash EEPROM, is known. The flash EEPROM is an important semiconductor device because of the expediency. The memory capacity increase and the development of a chip combined with a logic circuit, etc. are actively made.
The following are examples of related: Japanese Laid-open Patent Publication No. 08-288252, Japanese Laid-open Patent Publication No. 10-163456, Japanese Laid-open Patent Publication No. 2000-150678 and Japanese Laid-open Patent Publication No. 2003-168750.
However, as the devices are increasingly downsized, gaps between the memory cells are decreased. As a result, short defects between adjacent memory cells and between the memory cell and the bit line have often taken place due to fluctuations of the base structures and manufacturing conditions, etc.